Use of polyester powder in a shaping process, and moldings produced from this polyester powder

Abstract

The present invention relates to the use of a powder which comprises specific polyesters for shaping processes, and to moldings produced powder. The shaping processes are layer-by-layer processes which use powder, which comprises selectively melting regions of a powder layer by applying electromagnetic energy. Selectivity can although there is no intention to restrict the invention thereto be achieved via a mask, or application of an inhibitor, of an absorber or of a susceptor, or via focusing of the energy input. After cooling, the regions then solidified can be removed as moldings from the powder bed. The process occurs by using a polyester powder obtained from an alcohol and from a diacid with no use of any aromatic monomer unit. These polyester powders combine high crystallinity and low melting point, and makes the construction process more reliable while good component quality, mechanical properties, density, dimensional accuracy, and low shrinkage are realized.

The invention claimed is: 
     
       1. A layer-by-layer process for production of a three-dimensional component using a powder, which comprises:
 selectively melting regions of a powder layer by applying electromagnetic energy, 
 wherein the powder comprises at least one polyester prepared by polycondensation of a di- or polyhydric aliphatic alcohol and of an aliphatic diacid, 
 wherein 
 the melt flow rate value of the polyester powder to ISO 1133 is from 50 g/10 min to 500 g/10 min, 
 the melting point to DIN 53765 of the polyester powder is from 60° C. to 150° C.,
 the BET surface area of the polyester powder is less than 15 m 2 /g, and 
 
 the median grain diameter of the polyester powder is from 40 μm to 120 μm. 
 
     
     
       2. A process according to  claim 1 , wherein the dihydric aliphatic alcohol comprises at most 10 carbon atoms. 
     
     
       3. A process according to  claim 1 , wherein the dihydric aliphatic alcohol comprises at most 6 carbon atoms. 
     
     
       4. A process according to  claim 1 , wherein the dihydric aliphatic alcohol comprises at most 4 carbon atoms. 
     
     
       5. A process according to  claim 1 , wherein the powder comprises at least one polyester prepared via polycondensation of an at least trihydric alcohol and of a diacid. 
     
     
       6. A process according to  claim 1 , wherein the aliphatic diacid comprises 4 to 18 carbon atoms. 
     
     
       7. A process according to  claim 1 , wherein the aliphatic diacid comprises 4 to 12 carbon atoms. 
     
     
       8. A process according to  claim 1 , wherein the aliphatic diacid comprises 6 to 8 carbon atoms. 
     
     
       9. A process according to  claim 1 , wherein the aliphatic diacid is a saturated diacid. 
     
     
       10. A process according to  claim 1 , wherein the powder comprises at least one polyester prepared via polycondensation of a polyglycol and of an aliphatic diacid. 
     
     
       11. A process according to  claim 1 , wherein selectivity occurs by application of a susceptor, of an inhibitor, or of an absorber, or a mask. 
     
     
       12. A process according to  claim 1 , wherein selectivity occurs by focusing of a laser beam. 
     
     
       13. A process according to  claim 1 , wherein the powder is obtained by milling. 
     
     
       14. A process according to  claim 1 , wherein the melt flow rate value of the polyester powder to ISO 1133 is from 100 to 300 g/10 min. 
     
     
       15. A process according to  claim 1 , wherein the melting point to DIN 53765 of the polyester powder is from 60° C. to 120° C. 
     
     
       16. A process according to  claim 1 , wherein the melting point to DIN 53765 of the polyester powder is from 60° C. to 100° C. 
     
     
       17. A process according to  claim 1 , wherein the BET surface area of the polyester powder is less than 10 m 2 /g.